Police are treating the deaths of an elderly couple in Co Antrim as unexplained.
The bodies of Rita Boughey (79), and her 68-year-old husband Kenneth were found by a family member at their home in the Abbey area of Ballycastle on Thursday night.
It is believed they had been dead for several weeks.
Police Service of Northern Ireland (PSNI) chief inspector Mark McClarence said investigators were not ruling out the possibility of carbon monoxide poisoning.
“I appreciate there has been a lot of speculation and comment around carbon monoxide as a possibility (of causing death). We are keeping a very open mind around that possibility. The home is going to be examined and that will be one line of inquiry.”
The couple are originally from Liverpool and had lived in Spain before moving to Ballycastle about 10 years ago.
It is understood Mrs Boughey’s son discovered their bodies, believed to have been in separate rooms, when he visited the property after growing concerned.
Police, fire and ambulance crews were called to the house just after 8.30pm. Tests for potentially lethal levels of carbon monoxide were taken but none was detected.
“Fire Service did attend last night to check the property. At that stage it was safe for all the emergency services to enter; there was no sign of carbon monoxide,” Chief Insp McClarence added.
“However, we do appreciate that could have been from some time ago and that carbon monoxide may not be a factor now, today.”
Chief Insp McClarence appealed for anyone who was in contact with the couple in the past few weeks to come forward.
The Abbey is a new housing development comprising town houses and apartments on the site of a former convent close to the town centre.
Additional reporting: PA